


What We've Built

by WinterTheWriter



Series: Building Happily Ever After [30]
Category: The Avengers (Marvel Movies)
Genre: Angst, Bittersweet Ending, Brief mention of attempted self-harm, Euthanasia, Hurt/Comfort, M/M, Mentions of Cancer, Mentions of alcoholism, Moving On, New Beginnings, Parkinson's, Romance, finale
Language: English
Status: Completed
Published: 2017-06-07
Updated: 2017-06-07
Packaged: 2018-11-10 13:03:36
Rating: Explicit
Warnings: Major Character Death
Chapters: 3
Words: 2,614
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11127519
Author URL: https://archiveofourown.org/users/WinterTheWriter/pseuds/WinterTheWriter
Summary: The serum, unfortunately, is not magic. It can’t do everything; there simply comes a point where Nature wins and beats the accomplishments of man, just as it always has and presumably always will. Age is the only thing, including death, that will always be incurable. Even if the signs of aging never show, even if death never comes, we still grow older with every second that passes, we still bear the weight of time on our shoulders. The serum knows this. And so, in a slow, gradual build over the course of fifty years, it hands the reins of Steve Rogers’ body back over to Nature, not so much wearing off as it does gently bow and step away.





	1. Chapter 1

**Author's Note:**

> Here it is, guys. The end. Thank you so much for reading with me and giving this fic a chance. I know there's not a lot of you but you all count and I am genuinely so grateful I have any hits at all. This series has been my baby, and an absolute pleasure to write. I DO have plans for the future, but this series, this exact pairing, is at its end. 
> 
> (Note: Please read Building Blocks first! The missing scenes are important as this update calls back to it quite often to add to the emotional effects.)
> 
> Enjoy.

They both go to many more funerals together. 

It never gets easier. 

Tony, unfortunately, goes first. Years of drinking and partying and, ultimately, loneliness in love, finally catch up with him and he passes at the age of 72. They find him alone in his workshop, bent over a blueprint. 

Somehow, JARVIS cries. 

Surprisingly, at least to Steve, Koschei cries more than he does. He has the luxury of being ignorant of the domino effect Death has over humanity. 

This is the definite beginning of the end. 

~

Just as dominos within range of each other fall nearly together, Rhodey passes away only two short years after Tony. He has a full military funeral, and every US soldier in SHIELD (Steve included) wears full dress blues. Cancer, unfortunately, won in the end. 

He’d turned to smoking after Tony’s death. 

~

They have a full ten years after Rhodey’s death before they go to another funeral. 

Bruce’s, this time. He is 85. He is ready. Old age had made it harder to control the Hulk, and brittle bones meant that he came back to himself broken and in agony every time. His last invention is his own euthanasia. 

No one stops him. They all respect him too much for that. 

~

Fury dies in his sleep, at the age of 92. 

Natasha sobs openly for the first time. 

~

Natasha herself, fittingly, dies in the line of duty. Koschei thinks her death is the least fair of all, because she’s a super-soldier just like Steve. She’s caught in an explosion too extreme and concentrated to escape from, but she dies saving the world single-handedly. 

It reminds Koschei, more clearly than ever, how any mission can be their last. He starts to regret his words from the hospital, all those years ago. 

 

~

Clint goes next, unwilling and fighting and clawing away every step. He keeps fighting in Natasha’s honor, longer than anyone expected, but he was in his late 80s and still climbing up into the rafters, always the Hawk. All it takes is one misstep and one fatal fall. 

His last words are, “Not yet, not yet,” and Steve has to drag Koschei away from his body, who wouldn’t stop CPR even after he’s long gone. 

~

Last to go is Sam, who notices his hands won’t stop shaking at the age of 74. Parkinson’s takes him at 90 exactly, Koschei and Steve sitting on either side of him, the three of them cracking jokes and fake-smiles because Sam tells them he doesn’t wanna die depressed. There’s no heart monitor, no hospital, no “serious shit,” as Sam puts it. Sometime in, Sam just stops laughing at Steve’s jokes. 

Steve has to be sedated and carried out. 

~

And then, it’s only them left. Koschei and Steve, the last Avengers. Thor resigns after Jane’s death, ready to settle in as the true King of Asgard and live the rest of his days in his father’s footsteps. Stark Tower becomes a monument — unlived in but maintained. Steve outright refuses to let it become a museum, and he keeps all the rights to it Tony leaves him in his will. JARVIS looks over it like a cybernetic ghost, preparing it in the vain hope for future inhabitants. The couple retires to a nice apartment in Brooklyn, two blocks from where Steve was born.

Everything is…quiet. No aliens are invading, no humans come across trouble they cannot solve themselves, and to most of the world the Avengers become almost legend and, in a strange, roundabout way that makes Koschei’s stomach turn, fiction. 

It’s only been 45 years since Koschei joined the team.


	2. Chapter 2

The serum, unfortunately, is not magic. It can’t do everything; there simply comes a point where Nature wins and beats the accomplishments of man, just as it always has and presumably always will. Age is the only thing, including death, that will always be incurable. Even if the signs of aging never show, even if death never comes, we still grow older with every second that passes, we still bear the weight of time on our shoulders. The serum knows this. And so, in a slow, gradual build over the course of fifty years, it hands the reins of Steve Rogers’ body back over to Nature, not so much wearing off as it does gently bow and step away. 

It’s fine, according to Steve. He didn’t want to live forever anyways. 

 

Who would? 

~

The first fifty years of Steve and Koschei’s relationship is as blissful as it can be. Sure, there’s struggle and heartache, and fights and lonely nights and days where Koschei wonders if this is why the Doctor always had a new companion, and even days where Steve wonders the same thing, but every relationship, Koschei reasons, needs weakness to know strength. The majority of their time together is effortless and wonderful (and, truthfully, full of some really /fantastic/ sex) and that’s, in the end, what truly matters. 

They love each other. No two ways around it. They love each other and they make each other happier than they’ve ever been in their lives, and they have no regrets. Both of them step very carefully around the fact that, unless one of them commits suicide (which is he, most assuredly, not allowed to /ever/ do), only one of them will get the privilege of having the other for the rest of his life. 

And it’s not Koschei.

Which is fine. Koschei is fine with that. Human lives are fleeting and he’s known that, he’s always known that. A wise man once said you can live more in 20 years than in 80, and he was right. But, gods, does it get hard. 

At the nice young age of 150, Steve Rogers finds his first gray hair.

~

“Koschei! Koschei, babe, come here!” Steve /shouts/, far louder than necessary, and Koschei curses as he jolts up from bed and runs to the bathroom, all wild-eyed and scared.

“What?! What, what is it?!” he pants. Steve turns to him from staring into the mirror and pouts, holding up the front curl of his hair. 

“I have a gray hair! Me! I can’t get old yet!” With an exasperated sigh, Koschei relaxes and walks over to him, batting Steve’s hand out of the way to look himself. And there, just one little strand, but…gray. Definitely gray. 

“Huh.” 

“It’s gray, isn’t it? Am I seeing things?”

“No, that is most certainly a gray hair. …Oh, gods, I’m a trophy boyfriend now.” Koschei makes his best disgusted look until Steve pushes him and makes him laugh. “Darling, it’s /one/ gray hair. You’re fine. Still as gorgeous as always.” He very resolutely ignores the knot of panic in his gut, the desperate mantra of /not yet, not yet/ in his head. 

“Promise? I don’t look like a grandpa now?” Steve looks at him with big puppy dog eyes and Koschei grins, hands moving to grip his waist. 

“Definitely not a grandpa. Although…I can’t say I mind it,” Koschei hums, dotting little kisses along Steve’s neck. “I quite like the idea of having Captain America, silver fox, all to myself.” 

“Mmm. Don’t tempt me, or I’ll get it dyed gray professionally,” he chuckles, rubbing Koschei’s back. Koschei pauses and pulls back to silently raise an eyebrow at him. “Okay, no, I won’t,” Steve concedes, and Koschei immediately continues.

“Come on then, my love. Take me into the shower and show me how /young/ and spry you are.” 

And then Steve lifts him, just as easily as always, slams him into the shower wall, and they speak no more.

~

Dominos, Koschei muses one night, is a useless, stupid game that should be eradicated from the universe. 

It’s never just one gray hair. 

It never stays that way. 

~ 

In the middle of the night, 15 years later, Koschei wakes up for no particular reason, and finds that Steve is staring intently at the backs of his hands, furling and unfurling his fists with a pensive look on his face. Koschei yawns and rolls over to him, resting his head on Steve’s shoulder and gently petting Steve’s fist. 

“They look fine, darling,” he mumbles, voice thick with sleep. Steve sighs and kisses the top of his head.

“They look old,” Steve responds, resigned and indignant at the same time. “I look old.” 

This has been happening more and more recently. Koschei never expected Steve to obsess over his own aging more than he does. Tutting, Koschei lifts his head and presses a kiss to Steve’s jaw. “You look gorgeous. And you’re going to drive yourself insane overanalyzing every minuscule change in your body.” 

“I look old,” he repeats, not responding to the affection. Steve, maybe, looks like a well-aging man in his late 50’s. That, in Koschei’s opinion, is nowhere near /old/. 

Koschei tells him exactly that and Steve harrumphs before wrapping his arms around him, and settling them both back to sleep. 

~

The one saving grace is that Steve keeps his mind to the very end. Koschei doesn’t know if he could’ve survived being forgotten like that. 

You cannot build what you do not remember. 

~

Steve’s aging stops being an annoyance and morphs into an actual /problem/, an ever-growing thing they cannot ignore, when he is about 185. 

It’s all happening so fast, now. Steve stumbles when he stands, and he holds onto Koschei like he’s a walker rather than a lover, and his eyes crinkle too much when he smiles even though each and every moment of happiness and love is still just as heartbreakingly beautiful as ever. 

It’s exactly as Koschei predicted and he hates himself for it, like it’s his fault, so much that in a fit of manic terror and rage he almost cuts his own brain out of his head. Against all odds, it is the Master who stops him, emerging from the shadows of his mind to do his duty as Protector for the first and final time. 

He never tells this to Steve. 

~ 

“You live for me, my Koschei. You hear that?” Steve commands, smiling that same crooked grin even though he looks so sad, and so tired. Koschei nods tersely, his hands shaking in Steve’s grip. He’s trying so hard not to cry. He’s trying so hard to ignore the fact that they’re in a hospice, and this is real and happening, and the nurses called him in the middle of the night because they don’t think Steve will be here in the morning. 

How the hell can there even be a morning without him? 

Koschei has flashbacks to all their lazy Sundays, when everything was young and golden. He aches for those days so viscerally it almost makes him sick. 

He kisses Steve’s forehead, inhales raggedly when he pulls back and fakes a smile. Steve rolls his eyes, chuckling hollowly. “You’ve always been a terrible liar.” 

“What do you want?” Koschei blurts out. The words are harsh and crude but Steve, his Steve, knows exactly what he means. He knows it isn’t rhetorical. 

“The Avengers. Bring them back. We’ll have threats again someday and you’re the most qualified person for the job.”

“How?”

“Remember what we talked about, when we first got together?” 

Koschei nods, and Steve smiles again. He takes a wheezing breath and exhales it in a sigh, leaning back against the pillows.   
“My Koschei,” Steve murmurs, wistful and soft. “We did it, you know.” 

“Yeah?” Koschei sniffs, tries to hide it behind the question. “What did we do?”

“We built happily ever after. Brick by brick, you and me. Told you we’d make it.” 

And then Koschei’s smile /is/ genuine, because oh, he remembers that conversation. He remembers how glowing with hope Steve was, how deep and earnest his words were. “Suppose you’re right, love.” He reaches up a hand to stroke the paper-thin skin of Steve’s cheek, thumb brushing over the bone. 

They’ve never changed. 

Never in the ways that mattered. 

Steve shuts his eyes for a moment too long. When he opens them again, they’re gentle in a way that terrifies Koschei to the core. “It’s almost time.” 

He can’t help it. Koschei sobs. 

Steve, however, brilliant Steve, laughs airily like he was waiting for this and he weakly gathers Koschei as close as he can. Koschei sobs into his neck, mindful not to rest all of his weight on Steve’s chest. He’ll never be able to do that again. Steve shushes him gently and strokes his hair, pressing kiss after kiss against his forehead. 

Koschei forces himself to calm down, desperate to be strong for him one last time. When he pulls back, Steve’s skin is almost imperceptibly dimmer, and Koschei knows he’s right. Fuck, he knows. 

“What do you want?” Koschei asks again, this time quiet and calm. Steve hums thoughtfully for a moment, holding both of Koschei’s hands again. 

“A kiss. I want a kiss. I want you kissing me, the happiest place in my universe, to be the last moment of my life.” 

“Gods, Steve, I can’t —,” He’s only 200!

“You can. For me, you can. My brave man. My hero.” Koschei chokes on a sob and forces himself not to lose control again. He wins by a thread and nods, shaky and slow. 

“When?” he asks, voice barely above a whisper. 

“Mmm. Now.” 

“What? Already? Steve—,”

“Please, my dear.” 

“I-I…I love you. I love you so much. I’ll never be able to..to express h-how much I love you and even if I live another million years there is no language that—,”

“/Koschei/, I know. And you know every breath I’ve ever had carries my love for you, and now I am dying and I want you to kiss me.” 

Koschei almost doesn’t do it. It feels like sealing the deal. It feels like letting him go too soon. But…there is nothing he wouldn’t do for Steve. 

And so, going against every instinct in his body, Koschei leans in and kisses him, with all the love and intensity and passion of their first.

He keeps kissing him until Steve stops kissing back.


	3. Chapter 3

The new recruits are promising. 

Koschei’s been training them ruthlessly over the months, making sure to tend to each special talent and need his budding team requires of him. He becomes, he supposes, the patriarch of the Avengers, which is both fitting and wrong at the same time. 

His teammates are bubbling with excitement when he breaks the news — SHIELD has officially deemed them ready to become the Avengers once more, and take on missions and, most importantly, save the world. Koschei indulges their glee, lets them party and whoop and rope him into a celebratory dinner with them. It’s…good. Healing, if that’s possible. He’s making good on his promise and he’s keeping the Earth safe. 

They all move into Stark Tower officially a week later. Koschei stakes a vicious claim on his and Steve’s old room and everyone, smartly, never questions him. 

Everything is rebuilding, and renewing, slowly but surely. 

Their siren goes off in the middle of the night.

Koschei puts on the uniform. He got it tailored and fitted but otherwise unchanged — it’s the original, because he refused to have any other. That’s the deal. It fits perfectly, and it feels…right. It feels proper. Koschei nods to his reflection, and darts from his bedroom, grabbing the iconic star bulls-eyed shield from its perch and sliding it into his arm. 

Comm in ear. 

Everyone is ready. 

Everyone is waiting. 

They all watch him with bated breath, knowing his words but needing to hear them to make it official, make it real. 

Koschei smiles, slides down his cowl. Go time. 

“Avengers, assemble!”


End file.
